A very old specimen of wood contains 10^12 atoms of carbon: a) How many C-14 atoms did it contain in the year of 9474 B.C.? b) How many C-14 atoms did it contain in 2004 A.D.?
A radioactive sample consists of a mixture of S-35 and P-32. Initially, 5% of the activity is due to the S-35 and 95% due to the P-32. At what subsequent time will the activities of the two radionuclides in the sample be equal?
a) Tritium (H-3) has a radiological half-life of 12.3 years. What is its specific activity in units of Bq/g and Ci/g? b) A 0.2 gram sample of Kr-85 gas, which decays into stable Rb-85, is accidentally broken and escapes into a sealed warehouse measuring 40 x 30 x 20 m. What is the specific activity of the air inside in Bq/cm ...continues
Radioactive decay as a power source
Strontium-90 is to be used in a radioisotopic thermoelectric generator (RTG) for powering a navigation beacon located in the arctic. a) How much of the Sr-90 activity is required to generate 50 W of electric power if the conversion efficiency from heat to electricity is 30%? Tip: You must take into account the fact that Sr ...continues
Activity and activation cross section.
A cobalt foil, 1 cm diameter x 0.1 mm thick, is irradiated in a mean thermal flux of 10^11 n/cm^2-s for a period of 7 days. If the activation cross section is 36 barns and if the density of cobalt is 8.9 g/cm^3, what is the activity (Bq) at the end of the irradiation period?
You are a health physicist and you find an unknown contaminant that proves to be a pure beta emitter. To try to identify the contaminant, you attempt to determine the maximum energy of the beta rays. You use a GM tube with a thin (0.1 mm, ?=2.7 g/cm^3) end window. You find that 1.74 mm stops all of the beta particles. The di ...continues
a) How much energy does an alpha particle require to penetrate the minimal protective epidermal layer of skin (thickness~7mg/cm^2)? b) How much energy does an beta particle require to penetrate the minimal protective epidermal layer of skin (thickness~7mg/cm^2)?
A collimated beam of 200 keV gamma radiation delivers an incident energy flux of 2 J m^-2 s^-1 to a lead shield 1 g cm^-2 thick. a. What is the incident photon flux in photons cm^-2 s^-1? b. What is the rate of energy absorption in the shield in both erg g^-1 s^-1, J kg^-1 s^-1 and Gy s^-1
A collimated gamma ray beam consists of equal numbers of 0.1 MeV and 1.0 MeV photons. If the beam enters a 15 cm thick concrete shield, what is the relative portion of 1 MeV photons to 0.1 MeV photons in the emergent beam?
Assuming that the specific heat of the body is 1 cal g^-1 degrees C^-1, a) Plot the approximate temperature rise as a function of whole body dose ranging from 100 mGy to 10 Gy b) What absorbed dose would correspond to a potentially lethal heat body burden, assuming that a body temperature rise of 5 degrees C (normal body ...continues
